diff options
Diffstat (limited to 'fs/file_table.c')
-rw-r--r-- | fs/file_table.c | 42 |
1 files changed, 40 insertions, 2 deletions
diff --git a/fs/file_table.c b/fs/file_table.c index 986ff4ed0a7c..7a0a9b872251 100644 --- a/fs/file_table.c +++ b/fs/file_table.c @@ -42,6 +42,7 @@ static inline void file_free_rcu(struct rcu_head *head) static inline void file_free(struct file *f) { percpu_counter_dec(&nr_files); + file_check_state(f); call_rcu(&f->f_u.fu_rcuhead, file_free_rcu); } @@ -199,6 +200,18 @@ int init_file(struct file *file, struct vfsmount *mnt, struct dentry *dentry, file->f_mapping = dentry->d_inode->i_mapping; file->f_mode = mode; file->f_op = fop; + + /* + * These mounts don't really matter in practice + * for r/o bind mounts. They aren't userspace- + * visible. We do this for consistency, and so + * that we can do debugging checks at __fput() + */ + if ((mode & FMODE_WRITE) && !special_file(dentry->d_inode->i_mode)) { + file_take_write(file); + error = mnt_want_write(mnt); + WARN_ON(error); + } return error; } EXPORT_SYMBOL(init_file); @@ -211,6 +224,31 @@ void fput(struct file *file) EXPORT_SYMBOL(fput); +/** + * drop_file_write_access - give up ability to write to a file + * @file: the file to which we will stop writing + * + * This is a central place which will give up the ability + * to write to @file, along with access to write through + * its vfsmount. + */ +void drop_file_write_access(struct file *file) +{ + struct vfsmount *mnt = file->f_path.mnt; + struct dentry *dentry = file->f_path.dentry; + struct inode *inode = dentry->d_inode; + + put_write_access(inode); + + if (special_file(inode->i_mode)) + return; + if (file_check_writeable(file) != 0) + return; + mnt_drop_write(mnt); + file_release_write(file); +} +EXPORT_SYMBOL_GPL(drop_file_write_access); + /* __fput is called from task context when aio completion releases the last * last use of a struct file *. Do not use otherwise. */ @@ -236,10 +274,10 @@ void __fput(struct file *file) if (unlikely(S_ISCHR(inode->i_mode) && inode->i_cdev != NULL)) cdev_put(inode->i_cdev); fops_put(file->f_op); - if (file->f_mode & FMODE_WRITE) - put_write_access(inode); put_pid(file->f_owner.pid); file_kill(file); + if (file->f_mode & FMODE_WRITE) + drop_file_write_access(file); file->f_path.dentry = NULL; file->f_path.mnt = NULL; file_free(file); |